Vehicle underbody construction



Dec. 22, 1964 J. w. RICHARDS 3,162,478

VEHICLE UNDERBCDY CONSTRUCTION Filed Sept. 17, 1962 5 Sheets-Sheet 3Mgg/20% Dec. 22, 1964 J. w. RICHARDS VEHICLE UNDERBODY CONSTRUCTION 5Sheets-Sheet 4 Filed Sept. 17. 1962 Egg INV ENTOR.

ATTORNEYS Dec. 22, 1964 J. w. RICHARDS 3,162,478

VEHICLE UNDERBODY CONSTRUCTION Filed Sept. 1v, 1962 5 Sheets-Sheet 57215845 5V. P/V/RDS 1N VEN TOR.

fm j: 3%

Arriaa/vfrs United States Patent Oiilice 3,162,478 Patented Dec. 22,1964 3,162,478 VEHICLE UNDERBODY CNS'IRUCTIN Jesse W. Richards,Dearborn, Mich., assigner to Ford Motor Company, Dearborn, Mich., acorporation of Delaware Filed Sept. 17, 1962, Ser. No. 224,042 8 Claims.(Cl. 296-28) This invention relates generally to underbody structuresfor motor vehicles.

Most motor vehicles manufactured may be categorized as having a separatebody-on-frame construction or as having a fully unitized (frameless)construction. To provide the iine riding qualities demanded forpassenger carrying vehicles, either type of construction must haveresponse to road shocks, deflects as a unit or integralV beam. The bodyis attached to the frame by rubber body mounts which isolate the bodyfrom the frame and permit the body openings to remain dirnensionallystable even though the structural frame as a whole is detlecting.

The conventional fully unitized or frameless construction, whichfrequently is constructed according Vto the monocoque principle, dependson the body panels for its rigidity and on rigid body sills fordimensional stability of the body openings. Compliance must be achievedin the front and rear structural rails outside the confines of the bodysills.

The present invention adds to the body and frame construction and to theconventional, fully unitized construction a third and unique category ofvehicle construction which may be designated the integral frame-bodycombination. 1 'I'he unique underbody structure embodied in thisconstruction assures body rigidity, provides strong structural supportaround the passenger compartment` area, and permits a high degree ofstructural compliance. In this construction the body support is formedof heavy gauge, box section side sills and cross members which arewelded to the door pan. The junction of the body support with the frontrails is accomplished through torque boxes.

Although the use of torque boxes in vehicle frame construction is notnew, the integral frame-body construction of the present inventionemploys a novel design principle which is embodied as an Isolated TorqueBox Structure. The isolated torque box is isolated in a sense that it isnot integrally a part of the integrated body structure dash panel ortoeboard. The isolated torque box, one for each side of the integralframe-body, runs from the body sill laterally inboard to the front rail,so that vertical deilection of the front rail is accommodated bytwisting or torsional deflection ofthe torque box between the front railand the body sill structure, without causing transmission of the roadshock through theoor pan and into the passenger compartment of thevehicle.

One advantage of the isolated torque box construction and arrangement isthat the gauge and dimensions of the torque box can be so varied witheach Vehicle model as to obtain the degree of compliance that is mostcompatible with the balance of the vehicle structure.

Other objects, features and advantages of the present invention willappear in the following description and appended claims, reference beinghad to the accompanying drawings, in which:

FIG. 1 is a perspective view illustrating a vehicle underbodyconstruction in accordance with the present invention;

FIG. 2 is a perspective view of the vehicle underbody with thesuperstructure removed to bring out the framelike characteristics of theintegral frame-body construction;

FIG. 3 is an enlarged perspective View of a portion of the underbodyconstruction illustrating the isolated torque box;

FIG. 4 is a front elevation of FIG. 3;

FIGS. 5 and 6 are sectional views taken along the lines 5 5 and 6-6 ofFIG. 4, respectively; and

FIG. 7 is a schematic view comparing the'front rail deflectionobtainable with an integrated frame-body construction embodying thepresent invention with that of a conventional body-on-frameconstruction.

Referring now to the drawings, the underbody, generally designated 11,embodying the present invention comprises a body compartment door pan12. The iloor pan 12 is a large sheet metal panel having a drive shafttunnel 13 extending the full length of the pan and forming its centrallongitudinal structural reinforcing member. Lateral structuralreinforcement is obtained from channel offsets, such as the forwardoffsets 14 and 15 vand the rear oifset 16. These offsets have thefurther :function of providing platforms for the passenger compartmentseats (not shown). The floor pan is welded at each of its side edges toa heavy gauge, box section side sill 17. In addition to thereinforcement received from the channel offsets, thefloor pan isstructurallyreinforced froml the underside by channel shaped crossmembers 18 which extend laterally inwardly from the side sills andwhichv are welded to the -sills and to the door pan. v

The engine compartment area, which in FIGS. 1 and 2 of the drawing isshown forward of the passenger`com` partment area, is defined at itssides by spaced box section front rails 19, the front rails beingequidistantly spaced on each side of the longitudinal center of theunderbody and being substantially closer to each other than the sidesills 17. The rear end portion of each front rail is coupled -to thefront end portion of the adjacent side sill by a torque box 21, thestructural details of which at the front of the forward structure isprovided by diagl onal braces 25 which also carry the attachment for thefront mounting points of the suspension lower arms (not shown). Acrossthe front of the engine compartment structure is Welded the radiatorsupport assembly 26.

This Vassembly anchors the frontof the aprons ythrough its ownstructural rigidity and its attachment tothe front' frame cross member.Lateral stability Vbetween the rails andthe area of the suspension andfront engine mount attachment is aiforded by a bolted-in cross member27. v

Completing the engine compartment structure is the dash panel 28 whichis welded to the rearward ends of the aprons 22.

Although the structural features of the rear portion of the underbodyare not involved in the present invention, these features will bedescribed to present a complete description of the underbody. As mostclearly seenV from `FIG. 2, the box section body sills aremalzso con-:nected to the rear rails Z9 through `torque boxes 31.

However, the degree of freedom in uthe rear torque boxes is restrictedrelative. tothat achieved in Vthe front since l,

the rear torque boxes 31, the rear rails 29 and the iloor 3 A e pan 12are welded together into an integral construction. Therear rails 29 areinverted hat section members that are vwelded to the door pan.Transverse rigidity is achieved by another inverted hat section member32 running between the rails just forward of the kickup. This memberf32is also welded to the floor pan and it provides the upper attachmentprovisions for the rear shock aborbers (not shown).v vTying in the ends`of the rear rails is a Z'member 33y adjacent to the lower back panel34.

-iReferenceV is now made to FGS. 3 to 6, inclusive, which exemplifystructural details of the isolated torque box 21 embodied in the presentinvention. The views illlustratethe left front, junction betweenthe'portion of the underbody comprising the engine compartment andtheportionof the underbody comprising the passenger compartment.v It willbe understood that the structure at the other side of the underbody issymmetrical.

"-.Aslhas been briey described, the torque box 21 exhaving asubstantially planarY section 36 forming the base.'

of the box. The member 35 has an upwardly and forwardly inclined planarsection 37 which forms the rst or front wall ofthe box. This sectiondiminishes in height ,from the sidey sills 17 towardthe rail 19 so thatwheny viewed fromthe front of the unde'rbodyll itV has a substantiallytriangular appearance. The member 375 then has a. substantiallyvvertical planar section 38 which extends upwardly for a substantialdistance above the front Vor first wall 37 and which is welded alongitsfupper horiz ontal edge 39 to the dash panel 28.

1A, secondV sheet metal member 41 completes the' box. This memberhas asubstantially planar section 42 whichtis 54. This toeboard 54 is tied inat its upper edge to panel portion 39 and through this portion to thedash panel 28.

There is a substantial gap 55 between the rear wall 42 of the torque box22 and the toeboard 54. This gap extends the full length of the torquebox. The fact that this gap exists means that the torque boxl isisolated from direct contact with thel floor pan and therefore that anyreaction forces acting on the torque box which tend to deflect or twistthe latter are absorbed through the side sill and notby transmissionthrough the iloor pan into the vehicle body.

. To recapitulate, the front rail is'rattach'ed to the inner i end ofthe'torque box which runs laterally outward from the front rail to thebody sills. Because of this structural relationship of the front rail tothe torque box, the front rails are permitted to deflect in much thesame mannerV as the frame of a separate bodyframe structure deilects.That 1 A is, las the front wheels of the vehicle move across unevensurfaces, .the upward suspensionreaction forces tend to `Visl possibleto obtaintuneable structuralcompliance in inclined upwardly andforwardly to form the ,second or the latterl is provided with anges 44and 45 for weldingto, the sheet metalmember ;y

unitized vehicles similar to the compliance that is fundamental to thebody-on-frame type vehicles. In both types of' structures, it isnecessary toflimit deilections in thev body side framing in order topreserve door opening dimensions. Since the body'sills and rocker lareya part of the door opening frame of either structure, and also serveasthe principal structure of a unitized car, there is no opportunity topermit compliance in this area of unitized vehiclef The body-on-frametype ofvehicle hasthe principallower structure, the ychassis frame,separated by resilient Abody mounts from 'the body sills and rockers;

, therefore, compliance of the principal structure can be .The lateralends of the torque box 21`are4 welded Vto the i side sill 1.7'y and tothe front rail 19, tbe abuttingsheet rail 1 9. The section 42 isprovided at itsouter end, the; I end abutting the side sill .17, witharverticalflange 49,.y

which i'welded to theV inner side wall 51 of the sidesill' 11, Thevforward end of the side sin 17 femmmes, inthe anges V 52 on e of; theseanges being welded to theouter vertical ledge pof thersectionl of thesheet; metal member 35,., Ane'nd or coverv plate 5 3iswelded'acrossfthe; open endof thesidesill 17. f f

Itis; blsvedfthat ih 'fqrgqing brief description'lf' 'several of. theflanges and themethod of assembling the various components together issufficient fory anlunder- Y f standing Loffthe invention, since it willbeV understood that theiatta'chment of the various components followsconventionalpractice in thefconstruction of unitized vehicle bodies'. l

VA Kefelr`ing now toaFIG. 6, this cross-sectional` view CE2-flyillustrates an important feature of the present invention, thatgis, the'manner in which ,the torque box'21 is e Y isolated' lfrom'tlieffloirpan 12. As in most vconventional bodys'ytructur'es, whether of theA'separate body-`onrframe *type 9r PHD@ fully unitized type; th'oor, Pav12 termi nate ats'rfor'wardeendin atoeboard,` hereindesignated thes'ametotal deliection may be obtained as was obtained` ktheircompliance.

bers or torque boxes from the toeboard area,'none of their withoutdeparting from the Vspirit and scope tion, as dened .in the appendedclaims.

permitted as illustrated in the lower` half of FIG. 7. That is,'thefront portion of the frame maybepermitted to deflect in a verticaldirection as shown." f v Through theY present invention it ispossible toduplicate 'they unique characteristics of body-on-frame vehicles inunitized vehicles through the use of the Vcompliant members (theisolated torque kboxes 21) between the front side rails and the bodysills. These members can bethought Vof as shock absorbing compliantinserts in the unitized structure. Y T heyare located aheadof the bodyside framing, and thereby allow the use of rigid body side structures,yet provide for the 'absorption of shock through Bydivorcing thesecomplaint memmovement is transmittedy into the. floorof the" vehicle andwith the frame ofthe body-on-rame type vehicle.

f It will be understood that the invention is not tobe i limited to theexact construction shown and ies cribed, but

that var iousfchangesVV and modicationstmay. Vbe made of the-inve'n` Iclaim:v ,1 e, 1'. A vehicle u nderbodyAv assembly comprising:

v laterally spaced, longitudinally extending sills defining passengercompartment; porthe side perimetersxz-fl a tion of said ulnderbody,

laterally spaced, longitudinally'extending rails defining the sideperimeters of acompartment portion of said; v underbody at one-end ofsaid'passenger'compartment-l portion.y yand providing wheel suspensionVunit sup- Y ports,

Vthe sills beinggspaced laterally outwardlyy of the rails; torque boxmeans extendinglaterallyinboard from. onejj end portion of each sill toan adjacent end portion of each rail,

each torque box means being constructed and arranged to torsionallydeiiect about a transverse axis in response to Wheel suspension unitreaction forces acting on each rail, respectively,

and a oor panel connected at its lateral edges to said sills to form anintegral structure therewith,

said floor panel having an extension extending upwardly at an angle,

a portion of said extension overlying each torque box means with anisolation space therebetween,

said space isolating the torsional deection of each torque box meansfrom the adjacent portion of said extension and thereby inhibiting thetransmittal to said door pan through said extension of the reactionforces acting on each rail.

2. A vehicle underbody assembly comprising:

laterally spaced, longitudinally extending rails delining the sideperimeters of an engine compartment portion of said underbody andproviding front wheel suspension unit supports,

laterally spaced, longitudinally extending sills defining the sideperimeters of a passenger compartment portion of said underbody,

the sills having greater lateral displacement than the rails and beingdisplaced longitudinally rearwardly of the latter,

torque box means extending laterally inboard from the front end portionof each sill to the rear end portion of each rail,

each torque box means being constructed and arranged to torsionallydeflect about a transverse axis in response to front wheel suspensionunit reaction forces acting on each rail, respectively,

and a floor panel welded at its lateral edges to said sills to form anintegral structure therewith,

said floor panel having a toeboard extending forwardly and upwardly atan angle,

a portion of said toeboard overlying each torque box means withanisolation space therebetween,

said space isolating the torsional deecton of each torque box means fromthe adjacent portion of said toeboard and thereby inhibiting thetransmittal to said floor pan through said toeboard of the reactionforces acting on each rail.

3. A vehicle integral underbody structure comprising a body supportsection and an engine and wheel suspension support section:

said body support section comprising a floor pan,

side sills integrally connected to said door pan at the lateral edges ofthe latter,

and cross members extending from `said side sills beneath said door pan,

said cross members also being integrally connected to said ioor pan andto said side sills;

said engine and Wheel suspension support section coniprising box sectionfront rails,

upstanding aprons Welded to each front rail,

said upstanding aprons including wheel suspension mounting towers,

a front cross member tying the front ends of said front rails together,

a radiator support assembly extending across the front ends of saidaprons and above said front cross member,

and a dash panel extending across the rear ends of said aprons;

and torque boxes running from the body support section side sills andattached to the rear ends of said front rails,

said torque boxes being spaced from said dash panel and said floor pan,

said torque boxes being adapted to twist or rotate 6 about a lateralaxis in response to wheel suspension reaction forces acting on saidfront rails,

the spacing of said torque boxes from said dash panel and said floor panpreventing transmission of such 5 reaction forces back through thevehicle.

4. A vehicle integral underbody structure comprising a body supportsection and an engine and wheel suspension support section:

said body support section comprising a floor pan having an upwardly andforwardly extending toeboard,

side sills welded to said floor pan at the lateral edges of the latter,

and cross members extending from said side sills beneath said oor pan,

said cross members also being welded to said floor pan and to said sidesills;

said engine and wheel suspension support section comprising box sectionfront rails,

upstanding aprons welded to each front rail,

said upstanding aprons including wheel suspension mounting towers,

a front cross member tying the front ends of said front rails together,

a radiator support assembly extending across the front ends of saidaprons and above said front cross member,

and a dash panel extending across the rear ends of said aprons;

said toeboard being connected to said dash panel;

and torque boxes running from the body support section side sills andattached to the rear ends of said front rails, l

said torque boxes being spaced from said dash panel and said door pantoeboard,

said torque boxes being adapted to twist or rotate about a lateral axisin response to wheel suspension reaction forces acting on said frontrails,

the spacing of said torque boxes from said dash panel and said toeboardpreventing transmission of such reaction forces back through said iioorpan.

5. A vehicle integral underbody structure comprising a body supportsection and an engine and wheel suspension support section:

said body section comprising a oor pan having a toeboard extendingforwardly and upwardly at an angle,

box section side sills Welded to said floor pan at the lateral edges ofthe latter,

said engine and wheel suspension support section comprising box sectionside rails,

upstanding aprons welded to each side rail,

a box section cross member tying the front ends of said rails together,

a radiator support panel extending across the front ends of said apronsand above said box section cross member,

and a dash panel extending across the rear ends of said aprons andhaving said toeboard attached thereto at the upper end of the latter;

and torque boxes located beneath and in spaced relation to said toeboardand running from the body support section side sills to the rear ends ofsaid front rails,

said torque boxes being torsioned in response to Wheel suspensionreaction forces raising and lowering said front rails,

the space between said torque boxes and said toeboard being elective toisolate one from the other and inhibit the transmission of such reactionforces through the vehicle.

70 6. A vehicle integral underbody structure comprising a body supportsection and an engine and Wheel suspension support section:

said body section comprising an elongated door pan having a toeboardextending longitudinally forwardly and upwardly at an angle,

box SCCIion VSide sills welded to said floor pan at the lateral edgesofthe latter `and laterally extending crossmembers welded `into placeand extending beneath said floor pan from said side sills; .f t

said engine and wheel suspension support section cornprisinglongitudinally extending box section side rails terminating forwardly ofsaid side sills,

upstanding aprons welded to each front rail, i

a box section cross member tying the front ends of said rails together,n a radiator support panel extending across the front ends of saidaprons and above said box section cross member,

f and a dash panel extending across the rear ends of said aprons andhaving the upper edge of said toeboard attached thereto; v and torqueboxes located beneath and in spaced relationship to said toeboardandattached to theY front n endsrof said body supportsection side sills andto the rear ends of said side rails, Y i Y said torque boxes in responseto wheel suspension reaction forces raising and lowering said frontrails being torsioned about a lateral axis,

the space between said torque boxes and said toeboard` being effectiveto isolate one from the other and inhibit the transmission of suchreaction forces through said floor pan into the vehicle. 7. In a motorvehicle underbody structure: a longitudinally extending box sectionsill, a longitudinally extending box section rail,

at the ends thereof to said sill and rail,

vsaid sill and rail extending in opposite longitudinal directions fromsaid torque box;

'saidtorque' box comprising a first sheet metal member .Y and a secondsheet-metal member having and a transversely extending torque boxconnected.,

V(a) an inclined planar section 'forming Va second e wall of said boxextending transversely of said sill and rail, and (b) a planar sectionforming the top wall of said box; i Y said second sheet metal memberhaving flanges at each transverse edge thereof, e Y Y saidy anges beingattached to said first sheet metal member at'the transverse edgeopposite the junction Vof said base forming section and said rs'trwalland to the verticallyextending section above said sill and rail. v

8. In a motor Vehicle` underbody structure:

va longitudinally extending boxrsection sill,

a longitudinally extending box section rail,

and a transversely extending torque box connected at the ends thereof tosaid sill and rail,

said sill Vand rail extending in opposite longitudinal directions fromsaidY torque box; Y

said torque box comprising a first sheet metal member having n t (a) asubstantially planar section formingy the base of said box,

(b) an inclined planar section forming a first wall Y of said boxvextending transversely of saidv sill and rail and diminishing in heightfrom said sill t toward said rail, and (c) a vertically extending planarsection extend- Aing upwardly from said -Iirst wall and transverselyofsaid sill and rail, and a second sheet metal member having (a) aninclined planar section forming a second wall of said box extendingtransversely of said sill and rail, and .Y (b) a planar section formingthe top wall of said box; said second sheet metal member having flangesat each transverse edge thereof, said flanges being attached to said rstsheet metal member at the transverse edge opposite the junction lofsaid'base forming section and said rst Wall and to the verticallyextending section above said sill and rail, t the ends of said torquebox and the abutting portions of sill and rail being provided withilanges for integral attachment of the torque box to the sill and to therail.A

References Cited in the tile of this patent UNITED STATES PATENTSGermany Nov. 20, 1942

1. A VEHICLE UNDERBODY ASSEMBLY COMPRISING: LATERALLY SPACED, LONGITUDINALLY EXTENDING SILLS DEFINING THE SIDE PERIMETERS OF A PASSENGER COMPARTMENT PORTION OF SAID UNDERBODY, LATERALLY SPACED, LONGITUDINALLY EXTENDING RAILS DEFINING THE SIDE PERIMETERS OF A COMPARTMENT PORTION OF SAID UNDERBODY AT ONE END OF SAID PASSENGER COMPARTMENT PORTION AND PROVIDING WHEEL SUSPENSION UNIT SUPPORTS, THE SILLS BEING SPACED LATERALLY OUTWARDLY OF THE RAILS, TORQUE BOX MEANS EXTENDING LATERALLY INBOARD FROM ONE END PORTION OF EACH SILL TO AN ADJACENT END PORTION OF EACH RAIL, EACH TORQUE BOX MEANS BEING CONSTRUCTED AND ARRANGED TO TORSIONALLY DEFLECT ABOUT A TRANSVERSE AXIS IN RESPONSE TO WHEEL SUSPENSION UNIT REACTION FORCES ACTING ON EACH RAIL, RESPECTIVELY AND A FLOOR PANEL CONNECTED AT ITS LATERAL EDGES TO SAID SILLS TO FORM AN INTEGRAL STRUCTURE THEREWITH, SAID FLOOR PANEL HAVING AN EXTENSION EXTENDING UPWARDLY AT AN ANGLE, A PORTION OF SAID EXTENSION OVERLYING EACH TORQUE BOX MEANS WITH AN ISOLATION SPACE THEREBETWEEN, SAID SPACE ISOLATING THE TORSIONAL DEFLECTION OF EACH TORQUE BOX MEANS FROM THE ADJACENT PORTION OF SAID EXTENSION AND THEREBY INHIBITING THE TRANSMITTAL TO SAID FLOOR PAN THROUGH SAID EXTENSION OF THE REACTION FORCES ACTING ON EACH RAIL. 